Azuki bean (Vigna angularis) extract reduces oxidative stress and stimulates autophagy in the kidneys of streptozotocin-induced early diabetic rats.

Diabetic kidney disease is associated with oxidative stress, inflammation, and autophagy. The aim of this study was to investigate the effect of azuki bean (Vigna angularis) extract (ABE) on oxidative stress and autophagy in the kidneys of diabetic rats. Streptozotocin (STZ)-induced diabetic rats received 0, 10, or 40 mg/kg of ABE orally for 4 weeks, whereas vehicle-injected control rats received distilled water. Level of plasma glutathione and expression of heme oxygenase-1 (HO-1), p47phox (NADPH oxidase subunit), and markers associated with autophagy were examined. The glutathione level in the 40 mg/kg ABE-treated diabetic group (ABE-40 group) was higher than that of the untreated diabetic group (ABE-0 group). The HO-1 and p47phox protein expression levels of the ABE-40 group were lower (47% and 33%, respectively) than those of the ABE-0 group. The level of light chain 3B II (LC3B-II) was higher in the ABE-40 group than in the ABE-0 group. Protein levels of p62/sequestosome 1 (p62) in the ABE-40 group were lower than those in the ABE-0 group. Our results suggest that ABE may attenuate STZ-induced diabetic kidney injury by suppressing oxidative stress and (or) by upregulating autophagy.